1. Field of the Invention
The present invention relates to the field of data communications. In particular, the present invention relates to a method and apparatus to ensure proper association between electronics in a computer system.
2. General Background
Over the last decade, computers have become an important product for both commercial and personal use, in part due to their versatility. For example, computers are commonly used as a vehicle to transfer information over private or public networks. xe2x80x9cPrivate networksxe2x80x9d include a local area network or any network having restricted access, while xe2x80x9cpublic networksxe2x80x9d include the Internet or any network allowing access to the public at large.
In general, a computer comprises a chassis which encloses a number of circuit boards, normally including at least two backplanes. A xe2x80x9cbackplanexe2x80x9d is a circuit board including a plurality of connectors coupled together through a common bus. Each connector is capable of receiving a removable circuit board. Depending on the chosen computer architecture, backplanes may be situated proximate to each other or at opposite ends of the chassis.
In certain types of computers, one backplane may be arranged to receive one or more memory boards associated with a corresponding number of hard disk drives while another backplane is adapted to receive circuit boards to control the functionality of the hard disk drives (hereinafter referred to as xe2x80x9ccontroller boardsxe2x80x9d). This is accomplished by installing one or more cables between the controller board and the memory board(s) associated with the hard disk drive(s). Each cable comprises a plurality of signal lines, normally covered by as protective sheath, to transfer information from a source to a destination.
When each cable includes standard, interchangeable connectors, it is possible that a cable may be installed incorrectly, especially when blind (or hidden) cable routing needed for the computer architecture. Cable routing errors may occur at manufacturer or when the end user upgrades his or her computer with additional controller boards in order to support additional hard disk drives. For example, when installing additional or upgraded disk drives, a cable may be connected to the wrong controller board.
It is contemplated that cable routing errors may not be detected when they are not disruptive to the operations of the computer. However, in the event of a faulty hard disk drives, a cable routing error would cause the wrong disk drive to be identified as the malfunctioning drive. The reason is that error identification to the end user is based the physical placement of the hard disk drive in the chassis (or the disk drive number), not its true placement through cabling. While this problem may be overcome by customizing various cables and their mating connectors to lessen the chances of a cabling error, this solution is not cost effective.
Briefly, in one embodiment, the present invention relates to a method for determining a routing of cables between devices within a computer chassis. The method is comprised of signaling, for each of the devices, deactivation of a selected signal line of each cable. Then, one of the devices is requested to activate its selected signal line for one of the cables. The selected signal line is coupled to an input/output (I/O) data port of a driver circuit associated with the devices. The voltage on the I/O data port is sensed to determine which device is coupled to and in control of other device(s).